The present invention relates to a fluid cooling device with cooling, filtering and pumping means combined in one unit. In the fluid circuit, the fluid delivered by the pumping means can be filtered by the filtering means and can be cooled by the cooling means. The filtering means has at least one filter element which can be replaced when it becomes fouled.
In known solutions, DE-A-29 48 088, the disclosed pumping-cooling-filtering unit is a compact unit which is easy to install for filtered cooling circuits, preferably in a bypass flow. To connect the known fluid cooling device, hydraulic piping only to and from the tank and the voltage supply need be installed. The fluid cooling device, which can be connected in the bypass flow as important components, has a quietly operating delivery pump, a fluid filter and an oil-water plate heat exchanger. Applications of the known units are plastic injection molding machines, presses, machining centers, wind power plants and gearing.
The filtering means or the filter of the fluid cooling device should be changed from time to time depending on the degree of its fouling, i.e., replaced by a new means or filter unit. In known solutions, the entire fluid cooling device must be shut down. Also, the entire fluid system in which the fluid cooling device is being used must be turned off. Another possibility is to provide a change-over filter providing a filtered lubricating oil supply for changing the filter element as well. The change-over filter, however, occupies a relatively large amount of installation space and makes the known solutions overall more expensive (DE-A-42 37 028).
U.S. Pat. No. 3,741,342 discloses a generic fluid cooling device used in the lubricating circuit of motor vehicles to ensure, for the entire range of operating temperatures, that engine parts, such as the pistons, bearing rings, cams, etc., are adequately lubricated. For this purpose, lubricating oil, as the fluid from the xe2x80x9coilpanxe2x80x9d of the driving motor (engine), is relayed via a pump to a cooling means. The lubricating oil cooled in this way is relayed to a valve means located in the bypass to the two filter units. At low temperatures of the lubricating oil, the bypass valve allows direct lubrication of the driving motor, bypassing the filtering means. When the temperatures rise, the filters are then enlisted to filter the lubricating oil. If the pressure in the fluid or lubricating oil circuit continues to rise, which is generally the case when the temperature of the lubricating oil rises, another valve means is engaged for bypassing the filters and for supplying the heated lubricating oil directly to the cooling means to prevent damage to the filters and to improve the cooling situation in the lubricating circuit.
If the respective filter in the known fluid device needs to be replaced by a new one, the fluid cooling device must be shut down completely for changing of the filter element.
Objects of the present invention are to improve conventional fluid cooling devices so that the filter element can be changed without additional cost, even if the downstream lubricating oil supply is not shut down.
In the foregoing objects are basically obtained by a fluid cooling device combining cooling, filtering and pumping in one unit, comprising a fluid circuit, a pump in the fluid circuit for conveying fluid through the fluid circuit, a filter, with a replaceable filter element upon becoming fouled, in the fluid circuit, and a cooler for cooling fluid in the fluid circuit. A control valve in the fluid circuit separates the filter from the pump, while fluid continues to be supplied to the cooler for cooling, for replacement of the filter element. The control valve is actuatable by hand and has a catch retaining the control valve in a set position. A bypass connecting line in the fluid circuit extends parallel to the filter and connects to a supply line leading to the cooler for supplying fluid to the cooler when the filter is separated form the pump.
The foregoing objects are also obtained by a fluid cooling device combining cooling, filtering and pumping in one unit, comprising a fluid circuit, a pump in the fluid circuit for conveying fluid through the fluid circuit, a filter, with a replaceable filter element upon becoming fouled, in the fluid circuit, and a cooler for cooling fluid in the fluid circuit. A control valve in the fluid circuit separates the filter from the pump, while fluid continues to be supplied to the cooler for cooling, for replacement of the filter element. A bypass connecting line in the fluid circuit extends parallel to the filter and connects to a supply line leading to the cooler for supplying fluid to the cooler when said filter is separated from the pump. At least one check valve in the bypass connecting line opens in the direction of the cooler.
For replacement of the filter element in the fluid circuit, the control valve with which the filter unit can be separated from the fluid supply is provided. The cooling means continues to be supplied with the fluid to be cooled. The fluid flow or oil flow is routed past the filter which is to be changed via a bypass. Heated oil is cooled by the cooling means for further use in a machine doing mechanical work or the like.
The solution of the present invention can be economically implemented and allows safe changing of the filter element without the operator being exposed to safety hazards. Since the filter element is generally changed quickly, the contamination transferred via the bypass arrangement to fluid cooling can be tolerated and does not adversely affect subsequent fluid supply for a machine doing mechanical work.
In one preferred embodiment of the fluid cooling device of the present invention, for fluid supply of the cooling means within the fluid circuit in the bypass branch, a connecting line discharges or opens on the end side into the supply line for the filter and the cooling means. In this way, a fluid cooling device of especially compact structure is achieved. Preferably, the control valve can be actuated by hand and provided with a catch means which preserves the set position. This arrangement ensures operating reliability of the device.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.